<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .parent{
            width: 700px;
            height: 700px;
            border: 1px solid black;
            margin:0 auto;
            display: flex;
            flex-direction: row;

        }
        .child{
            flex: 1;
            height: 60px;
            color: white;
            
        }
        .midle{
            flex: 2;
        }
    </style>
</head>
<body>
   <div class="parent">
    <div class="child" style="background-color: blue;">地图1</div>
    <div class="child midle" style="background-color: rgb(203, 107, 42);">地图2</div>
    <div class="child" style="background-color:rgb(57, 207, 157);">地图3</div>
   </div>
</body>
</html>